Corrugator Print Dimension Control Under Heat and Humidity
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Solution Overview
Problem
Existing corrugated board machines face challenges in maintaining dimensional accuracy of printed images due to shrinkage caused by temperature and humidity changes during the production process, leading to inefficiencies and rejects when adjusting the converting process.
Innovation Solution
A method and system for controlling the shrinkage of printed images by using a controller to adjust processing parameters based on actual and target final dimensions, minimizing errors through actuator intervention, independent of web speed variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional steam-heating systems are used for heating platens, then heating capability is provided, but thermal response time is slow and energy efficiency is poor
Solution Approach 1:
The patent replaces the conventional steam-heating mechanical system with an electrical heating system using heating elements embedded in or adjacent to the platens. This substitution enables direct electrical resistance heating, providing rapid thermal response and precise temperature control while eliminating the delays associated with steam generation and heat transfer through platen thickness.
2Temperature
If conventional steam-heating systems are used for heating platens, then heating capability is provided, but energy consumption is high
Solution Approach 1:
The patent replaces the steam-generation and heat-transfer mechanical system with direct electrical heating elements, eliminating energy losses associated with boiler efficiency, steam condensation, and heat transfer through thick platen materials. The heating elements provide direct contact heating with superior energy efficiency and reduced consumption.
Solution Approach 2:
The heating system is segmented into multiple independent heating zones with individual heating elements positioned at different locations within the platen structure. This segmentation allows selective heating of only the zones requiring temperature control, reducing overall energy consumption while maintaining precise temperature distribution across the platen surface.
3Quantity of substance
If adhesive is applied too early in the corrugation process, then adhesive coverage is achieved, but adhesive sets before reaching the bonding zone causing poor bond strength
Solution Approach 1:
The patent applies adhesive to the fluted medium in advance before the bonding zone, utilizing the warmth retained from the preheating section to maintain adhesive workability. This preliminary application allows adequate adhesive coverage while the retained heat prevents premature setting, ensuring proper bonding when the surfaces are joined in the bonding zone.
Solution Approach 2:
The patent utilizes temperature as a controllable parameter, maintaining the adhesive application zone at an elevated temperature to extend the adhesive's open time. By controlling the temperature parameter in the preheating section, the adhesive remains workable and does not set prematurely, allowing proper bonding to occur when the surfaces are joined.
4Reliability
If adhesive is applied too late in the corrugation process, then adhesive freshness is maintained, but insufficient preheating occurs resulting in poor bonding
Solution Approach 1:
The patent implements preliminary heating of the fluted medium in a dedicated preheating section before the bonding zone, ensuring the substrate reaches optimal temperature for adhesive bonding. This preliminary thermal preparation occurs before adhesive application, creating ideal conditions for subsequent adhesive effectiveness and strong bonding.
5Temperature
If multiple separate heating zones are used for different sections, then temperature control precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the heating system into multiple independent zones with separate heating elements positioned in the preheating section, bonding zone, and cooling section. Each zone can be independently controlled to maintain optimal temperature profiles throughout the corrugation process, achieving precise temperature control without excessive complexity through modular zone design.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures flexible operation with maintained dimensional accuracy of printed images, reducing rejects and allowing for variable web speed without compromising image quality.
Implementation Method 1
at least one heating element arranged to heat the fluted medium
Implementation Method 2
an adhesive layer is applied to the fluted medium in the preheating section
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a method for operating a corrugator (2), wherein a plurality of webs (8, 8a) in a process section (10) of the corrugator (2) are connected to form a corrugated board web (12), wherein one of the webs (8, 8a) is printed with a printed image (38) which has a number of recurring printed image elements (40), wherein for the printed image (38) a target final dimension (MS) is specified which is to be present downstream of the process section (10), wherein the printed image (38) downstream of the process section (10) has an actual final dimension (MI) which is measured by means of a measuring unit (42), wherein by means of the actual final dimension (MI) and the target final dimension (MS) a final dimension fault (ΔM) is determined, wherein the corrugator (2) has a controller (4) which controls the process section (10) depending on the final dimension fault (ΔM) in order to minimise said final dimension fault (ΔM). The invention also relates to a corresponding corrugator (2).